Morphological analysis is a process of dividing a text into morphemes and assigning information about parts of speech to each morpheme. In some cases, each morpheme obtained by using the morphological analysis is used as a word.
A document information storage apparatus that encodes and stores morphemes extracted from document information has been known (see, for example, PTL 1). The document information storage apparatus performs the morphological analysis to extract the morphemes from inputted document information as components of the document information, encodes the extracted morphemes, compresses the encoded morphemes, and stores the compressed encoded morphemes in a storage unit.